A man shot four men with whom he had worked -- two of them fatally -- in northern Florida on Saturday before shooting and killing himself , the Union County sheriff said .

Sheriff Jerry Whitehead told CNN affiliate WJXT that the Lake Butler `` community is in shock , '' after 72-year-old Hubert Allen Jr. allegedly went on a shooting spree , killing his longtime boss , Marvin Pritchett , 80 , and a former co-worker Rolando Gonzalez-Delgado , 28 .

Two other men were shot and wounded .

Whitehead said he knew all of the individuals and is Pritchett 's nephew .

Lake Butler , where most of the shootings took place , is a small community of fewer than 2,000 residents .

Whitehead said Pritchett was a `` self-made millionaire '' and `` just a great guy , with a great family . ''

Pritchett 's death will have a `` terrible impact on the community , '' Whitehead said .

Whitehead knew Allen for 40 years , and said he 'd just talked to him just last week .

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Allen was the step-grandfather of Buffalo Bills running back C.J. Spiller , the sheriff said .

A law enforcement authority with detailed knowledge of the case said the gunman had an argument with Pritchett earlier in the week , The same source clarified an earlier report , saying the argument happened Monday and that the gunman was retired from the company , though he was still involved in some capacity and still interacted with its owner .

Whitehead said he could n't confirm any details related to a motive , but that his department was investigating .

The Union County Sheriff 's Office said Allen went to a Lake Butler farm owned by Pritchett , where he fatally shot Gonzalez-Delgado .

A short distance away , Allen shot and killed Pritchett , authorities said .

From there , police said Allen confronted another former colleague driving a farm tractor . The men exchanged words before Allen fired a shot at 66-year-old Lewis `` Buddy '' Mabrey Jr. , striking him in the left arm and side .

Mabrey was rushed to the hospital , where he was expected to undergo surgery for a broken arm and other injuries . He was in good condition .

Allen traveled to Pritchett Trucking Inc. and shot a third co-worker , 44-year old David Griffis , in the stomach , officials said .

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Griffis was taken to the hospital for immediate surgery ; he was in critical condition .

The suspect then fled the scene to his home , where he shot and killed himself , officials said .

Police say they believe Allen acted alone in these shootings , but they continue to investigate the `` heinous crimes . ''

A statement posted Saturday evening on the company 's website said Pritchett Trucking was shocked and mourning the loss of its founder and the employees .

`` Words can not express the pain and sorrow felt by so many , yet we are comforted by the memories of those lost . ''

According to the site , Marvin H. Pritchett founded Pritchett Trucking Inc. in 1980 . The company employs `` well over 400 people and is apportioned in all 48 states and Canada . ''

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Suspect was step-grandfather of NFL star

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Sheriff says he knew suspect , victims personally

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Victims were owner , employees of Pritchett Trucking

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Suspect , 72 , was retired , but still interacted with business